The invention relates to an electrical plug-in connection for an automatic transmission of a motor vehicle to transmit signals required for control of the hydraulic control device which signals are received from an electronic control device provided outside the transmission.
The invention especially relates to the electrical plug-in connection for an electrohydraulic automatic transmission usually consisting of a starting unit such as a hydrodynamic converter, clutches and brakes, a hydraulic control device and an electronic transmission control device. The electronic transmission control device forms, from input variables, the parameters needed for the control of the automatic transmission. Input variables are signals already supplied by sensors and signals made available by other control device such as the motor control device. The electronic transmission control device controls via output signals the electromagnetic actuators located in the hydraulic control device. Shifts are initiated, via said electromagnetic actuators, by selecting an adequate clutch/brake combination. The pressure curve during the shift and the pressure level outside the shift are additionally controlled via the electromagnetic actuators.
The hydraulic control device is often mounted upon the underside of the automatic transmission and comprises a suction snorkel, a valve housing, an intermediate plate with seal and a duct plate, the duct plate and the transmission housing coming to abutment with each other via two faces.
Automatic transmissions for motor vehicles have an electrohydraulic control generally installed horizontally or vertically and containing the electromechanical and electronic parts which are to be connected with a cable harness situated outside the transmission, for example, to supply voltage. DE 43 44 584 describes by way of example a system of magnetic valves, a central plug and a printer board for a hydraulic transmission control device. The electrical lines in the proximity of the electronic module within the transmission are laid out as massive flat lines in the form of a pressed screen or of a flexible printed board. The pressed screens or printed boards are then connected with a socket placed in the transmission housing after which the electrical connection to the vehicle cable harness is created by inserting a mating plug.
Automatic transmissions are already known wherein an electronic transmission control is integrated in the transmission and situated directly on the hydraulic control.
In order to make possible a socket in a horizontal direction in a recess of a perpendicular wall of a transmission housing, it has already been proposed in the Applicant""s DE 199 22 819.1 to produce a pressed screen, that is, a two-dimensional arrangement and after insertion in the module carrier, e.g., by an extrusion coating or clamping, to connect it by soldering, welding or riveting with the individual electrical and electronic parts. Thereafter, the socket in a vertical position, that is, with a downwardly directed plug opening, is connected with the pressed screen and after contact has occurred, an end of the pressed screen is bent together with the socket by about 90xc2x0 depending on the installation position so that the transmission socket comes to a horizontal position. Thereafter, the socket is moved back relative to its final position to the extent that upon vertical insertion of the electrohydraulic control, the socket does not border on the inner wall of the transmission housing. After complete mounting of the -control, the socket is located in prolongation of the installation position behind the port in the transmission housing.
In DE 199 03 712, an electrical plug-in connector to be used with transmission control systems in motor vehicles has already been proposed in order to create an electrical connection between two electrical areas separated from each other by a wall, which comprises a first plug-in connection part that carries electrical plug-in contacts, a second plug-in connection part that contains electric contact bushings and a guide sleeve designed for gripping through an assembly port located in a wall and having the first plug-in connection part at one end and the second plug-connection part at the other end, means being provided for fixing to the wall. The means for connecting the guide sleeve that grips through the wall with the plug-in connection part located behind it can be designed as a kind of thread or a kind of bayonet locking system. The electrical connection between the inaccessible plug-in connection part which is, for example, the plug part provided with a pin housing, and the electrical and/or electronic components situated upon a circuit carrier spaced from the plug-in connection part can be implemented by flexible conductors such as sheet conductors.
In all said electrical plug-in connections known already the socket or plug parts serving as mating plugs are situated in the transmission housing. But in newer transmission such as have now been developed it is no longer possible to assembly one part of the electrical plug-in connection in the transmission housing as a mechatronic solution.
The problem to be solved by this invention is to provide an electrical plug-in connection for the automatic transmission of a motor vehicle where a reliable, safe and automatic connection is made possible despite the disadvantages of modern transmissions determined by installation space.
It is therefore provided, according to the invention, that the electrical plug-in connection consisting of a transmission socket fixedly situated to the transmission and electrically connected with the electrohydraulic automatic control and of a plug part engaging therein, which is electrically connected with the vehicle cable harness, be configured in a manner such that the socket is inserted in the oil pan of the transmission; when the oil pan and the transmission housing are assembled, an electrical contact occurs and when they are disassembled said electrical contact is disrupted. Via the vehicle cable harness the electrohydraulic transmission control device is supplied, for example, with the vehicle voltage and/or connected with other electronic devices.
In case of an oil pan consisting of plastic material, it is of special advantage that the socket be fixedly connected with the oil pan by injection molding during production.
This firm assembly of the transmission socket (or of the transmission plug) in the oil pan eliminates a subsequent assembly of the plug-in connection in the oil pan which would be extremely unfavorable due to sealing problems or to the narrow installation space. Thereby a tying by a cable harness is also eliminated which is extremely problematic for reasons of cost, and also the oil pan in disassembled state does not adhere to the transmission plug, as would be the case were a cable harness used.